Recent advances in the epidemiology and genetics of acute intermittent porphyria
INTRACTABLE & RARE DISEASES RESEARCH
Authors: Ma, Liyan; Tian, Yu; Peng, Chenxing; Zhang, Yiran; Zhang, Songyun
Abstract
Acute intermittent porphyria (AIP) is a dominant inherited disorder with a low penetrance that is caused by mutations in the gene coding for hydroxymethylbilane synthase (HMBS). Information about the epidemiology and molecular genetic features of this rare disorder is crucial to clinical research, and particularly to the evaluation of new treatments. Variations in the prevalence and penetrance of AIP in various studies may due to the different inclusion criteria and methods of assessment. Here, the prevalence and penetrance of AIP are analyzed systematically, and the genetic traits of different populations and findings regarding the genotype-phenotype correlation are summarized. In addition, quite a few studies have indicated that AIP susceptibility was affected by other factors, such as modifying genes. Findings regarding possible modifying genes are documented here, helping to reveal the pathogenesis of and treatments for AIP. The status of research on AIP in China reveals the lack of epidemiological and genetic studies of the Chinese population, a situation that needs to be promptly remedied.
New insights into the physics of rotating spokes in partially magnetized E x B plasmas
PHYSICS OF PLASMAS
Authors: Boeuf, J. P.; Takahashi, M.
Abstract
Regions of enhanced light emission rotating in the azimuthal direction ("rotating spokes") have been observed in different types of partially magnetized E x B plasma devices such as magnetron discharges and Hall thrusters. A two-dimensional Particle-In-Cell Monte Carlo Collision (PIC MCC) model is used to study the formation of these rotating structures. The model shows that these current driven rotating structures are the results of a Simon-Hoh instability evolving into an ionization instability. The spoke is sustained by local electron heating induced by del B drift along a double layer separating the cathodic presheath from the plasma at a potential close to the anode potential. The PIC MCC simulations predict that spoke rotation can take place in the +E x B direction and in the -E x B direction depending on the magnetic field intensity. Published under license by AIP Publishing.